Furnace for heating fluids



1957 K. B. WESTMAN 2,800,125

FURNACE F'OR HEATING mums Filed May 17. 1954 I INVENTOR 4 K8. WESTMAN ATTORNEYS United States PatcjtttiC FURNACE FOR HEATING FLUIDS Kjell Birger Westman, Johanneshov, Stockholm, Sweden Application May 17, 1954, Serial No. 430,325 7 Claims. (c1. 126-'-106)' be used to heat airplane engines under temporary shel-.

tors in cold climates. p V

In heating devices or furnaces of this kind there are several primary desiderata such as efficiency, durability, and for a heating unit to be used for instance at military bases, to warm up airplane engines, portability due to compactness and light weight is important.

Traditionally space heaters, stoves, domestic furnaces and so forth have been bulky, heavy, uneconomical in operation and difficult to clean.

An object of the present invention is to provide a compact, light weight, efiicient heat exchange device that may be used even when electric power is not available.

A further object of the present invention is to provide a furnace including means to clean the flues without disassembly of the device, in order that the elficiency of the furnace will be maintained.

A further object of the invention is to provide a heating unit that may be disassembled into a few lightweight elements for transportation.

A further object is to provide a heating unit that is inexpensive to manufacture.

Other and further objects and advantages will appear, to those skilled in the art, from the following description taken in connection with the accompanying drawings in which like characters of reference designate corresponding parts in the several views and in which:

Figure l is a vertical section of the device,

Figure 2 is a horizontal section taken at 2--2 in Figure 1,

Figure 3 is a horizontal section taken at 3-3 of Figure 1, and

Figure 4 is a fragmentary viewsimilar toFig'ure 1 showing a modification.

In the drawings, 1 is the fire box which is the lower part of what I call the primary channel system. This primary channel system includes the fire box and flues. The secondary channel system is denoted by the numerals 2 and 3 and includes baflle or shell walls 4 and 5 that force the heating medium to follow the desired paths through the secondary channel system. Shells 4 and 5 may be of heat insulating material as for instance by being of two sheets of steel, with asbestos, silica, etc. between the sheets. Fins 27 may be provided on the outer wall of fire box 1 to increase the heat exchange area and to space the shell 4 from the fire box.

Cylindrical elements 6, 7, 8 and 9 are connected together by appropriate horizontal plate. rings to form one unit and cylindrical elements 10, 11 and 12 are similar i atented July 23, 1957 ice 1y secured together to form a second unit. When these two units are assembled together, they are secured at junction I3'and' the flue portion of the device is substantially complete. Junction 13 is the only joint in the primary channel system or flue passage and is readily accessable to ensure tightness. It will be seen from the drawing that the upper portion of the ensemblage is made up of successive pairs of parallel plates alternating with successive pairs of spaced cylinders to form a heat exchange flue portion through which the hot combustion gases flow-against a very great area of flue wall to give themaximum heat exchange area.

Surrounding fire box 1 and its shell 4 and extending upwardly to a point somewhat below joint 13 is an ann'ular outer casing 37 through which the fire door 19, burner 25 and pipe 24 extend. The outer casing is continued upwardly by an annular cowl 38, 39 and 40 that fits tightly with a friction fit over casing element 37 and also fits snugly on pipe 23. The pipe 40 at the apex of the c'ow'l is connectedto the heating fluid circulating systern.

Mounted just below the horizontal plate 10 at the topof cylindrical element 10 is a soot cleaning device 14' which has a vertical pivot 14 extending upwardly through the plate 10. The upper end of the pivot is connected by a flexible connection to an acuating means 29 that may be engaged by a wrench. Soot cleaner arms 14-exter'ids downwardly between cylindrical elements 8 and 10, thence horizontally outwardly, thence upwardly between cylindrical elements 9' and 11. Cleaner arms 14 has mounted on its cleaning elements 34 that knock the 'soot' off of the cylindrical elements. Soot that falls between cylindrical'elements '8 and 9 will be swept into soot collector box or drawer 17 which may be cleaned out by use of an access opening 16 provided in the outer casin'gof the'device.

Just above plate 10' and surrounding the vertical shaft 14' is a humidifying element 26 which when provided with waterfrom' a small tube (not shown) evaporates the waterinto steam as the bottom of element 26 is plate '10 which is heated directly'from the hot gases from the fire box.

It will be noted that at the top of cylindrical element 11 is a liorizontalplate 11" and at the top of cylindrical element '9' where it is joined to the inner unit there is a horizontal plate 13. These plates are connected by cylindrical element 11" to provide an eccentric opening for the circulation of the heat transfer fluid, such as air, gas, or even liquid.

As seen in Figure 2 there is a flue gas uptake or flue pipe I-Zueccentric to the heating unit that withdraws flue gas from the space in the primary channel system or flue between plates 11' and 13. An economizer'32 may be mounted on pipe 12 beyond the 'heating unit, if desired, as seen in Figure 2.

In the side of fire box 1 is a conventional fire door 19. Below fire door 19 is shown an oil burner 25. In case of need, as for instance in the absence of electric power, a grate'c'an be inserted in lieu of the oil burner and solid fuel can be burned. The bottom 15 of the tire box is closed and acts as an ash'pit' when solid fuel is used.

Below fire box 1 on a suitable support a fan 20 is mounted coaxially of the assembly. This fan takes heat tric motor 21, if electric power is available, and may be driven by internal combustion engine 28 if electric power is not available. A lower casing part 37 houses'this assemblage.

' ar the bottom of electric motor 21' located ruel oil pump 22 to provide fuel under pressure to burner 25. It will be noted that as the speed of the motor is varied the fan 20 and burner 25 are synchronized so that under variable-conditions of load the volume and temperature of heating medium may be regulated.

In operation afire, either oil or solid fuel, burns in fire box 1 and the flue gases heat the Walls of fire box 1,

pass upwardly in the primary channel through flue 7,

fan 29 passes upwardly against the inner periphery of the casing and outside of partition 4. At the top of the fire box the air current is normally divided into two parts, one part flowing inwardly against plate 8' to pass up inside of element 8 and up over the top edge of shell 4, thence downwardly between shell 4 and the wall of the fire box 1 to discharge pipe 24.

The other portion of the fluid not to be discharged through element 24 passes upwardly about element 9 and up over plate 13. Shell 5 requires this fluid to follow around in a tortuous path against the surfaces of elements 11", plate 11, element 11, element and plate 10', thence up discharge pipe 23.

It will be noted in Figure 4 that a connection is indicated at 31 through the casing into'the secondary channel system above the level of plate 8'. By provision of a plate 39, shown as a continuation of plate 8 that extends to the casing instead of stopping at pipe 9, the secondary channel system may be divided into two parts and the heat transfer fluid heated in each part will be kept quite separate to make, in fact, two separate heating circuits. These two heating circuits may use dissimilar heat transfer fluids.

Therefore, and as shown in the drawings, my invention provides a heating furnace comprising a casing formed by the bottom unit 37, the intermediate unit 37 and the upper unit 38 including the top 39. The top 39 has a port for the flue gas uptake 12 formed therein and carries 'a pipe 23 forming an outlet for heated fluid. Within the casing and spaced from the walls thereof is a combustion chamber 1 which has a closed bottom and open top or upper outlet. The wall means that define a tortuous flue extend between the outlet of the combustion chamber and the flue gas outlet or uptake in the top. These wall means include plural vertical walls 8, 9, 10, 11 and 11" and plural horizontal walls 7', 8', 11 and 13. These vertical and horizontal walls are respectively spaced from the Walls and top of the casing and from each other so as to define inner and outer vertical passage portions and upper, intermediate and lower horizontal passage portions. The flue gas outlet communicates with the upper horizontal passage portion. A shell means including wall 4 spacedly surrounds the combustion chamber, has a closed bottom and an open top. The open top terminates beneath the wall 7 forming part of the intermediate horizontal passage portion and is located inwardly and spaced from the wall 8 forming part of the inner vertical passage portion. The casing has an outlet means at 24 communicating with the space between the shell 4 and the combustion chamber. Tubular means 23 and shell 5 provide communication between the outlet in the top for combustion chamber .15 and the plural passage portions 4 for the flue gas passage in heat exchange relationship. Further, as pointed out hereinbei'ore, a flue portion includes a first unit comprising the lower wall 7 of the intermediate horizontal passage portion, the innermost wall 8 of the inner vertical passage portion, the lower wall 8', the lower horizontal passage portion and the outer wall 9 of the outer vertical passage portion. The upper part of the wall 9 also forms the outer wall of the upper horizontal passage portion. The second unit of interconnected walls comprises the upper walls of the respective horizontal passage portions as at 13, 10 and 8", the outer wall 10 of the inner vertical passage portion, the inner wall 11 of the outer vertical passage portion, the lower wall 11" of the upper horizontal passage portion and the inner wall 11" of the upper horizontal passage portion. These units are connected together by a joint at 13 which is provided between the upper wall of the upper horizontal passage portion and the outer wall 9. The tubular combined passage and baffle or shell element 5 is supported in relation to the upper wall 10' by web portions 23. Further, the invention may include a wall 30 that is'formed as an extension between the wall 8 and the casing wall to permit two fluids to be heated, one by the lower portion of the flue and by the combustion chamber, the other by the upper portion of the flue; To provide for this double fluid circulation another inlet at 31 communicates with the space above the Wall 30. As another important feature, the passage at 25' feeds combustion supporting air to burner 25 from a space within the casing above the fan on impeller means 20.

Although only one embodiment of the heating device of the present invention is shown and described herein, it should be understood that the device is capable of other adjustment and modification without departing from the spirit and scope of the appended claims.

What is claimed is:

1. A heating device for heating fluid comprising wall means forming a combustion chamber, a flue connection, a heat exchange means to receive combustion gases from said combustion chamber and to conduct them to said flue connection, a casing surrounding said combustion chamber and said heat exchange means in spaced relation thereto, said casing having, at least one inlet for fluid to be heated and at least one outlet for heated fluid, said flue connection extending from said heat exchange means through said casing, said wall'means comprising a generally cylindrical wall, a closed bottom, and a top closed except for an axial cylindrical gas outlet flue mounted on said top, said heat exchange means constituting a continuous gas tight flue passage leading from said cylindrical gas outlet flue to said flue connection through said casing and providing an interior hollow fluid heating space, said heat exchange means comprising a first pair of spaced plates lying in parallel planes normal to the axis of said combustion chamber forming a first horizontal passage portion, one of said plates forming a radial extension of the top edge of said cylindrical gas outlet flue, and comprising successive pairs of coaxial spaced cylinders forming walls of cylindrical passages and axially spaced radially extending plate elements connecting each pair of spaced cylinders with a succeeding pair of spaced cylinders to form at least one horizontal passage therebetween, said heat exchange means terminating with a last pair of radially extending plate elements connected by a cylindrical wall spaced radially inwardly of the preceding pair of spaced cylinders and the uppermost of said last-mentioned pairs of radially extending plate elements being provided with an opening to said flue connection, and a shell extending from said outlet for said heated fluid into the interior of said hollow fluid heating space and spaced from said heat exchange means to form a heat exchange passage.

2. A heating device as claimed in claim 1 in which an overlapping joint between the edges of the upper of said last pair of radially extending plates and the outer of the next preceding pair of spaced cylinders constitutes the sole joining means by which the heat exchange flue portion may be assembled.

3. A heating device as claimed in claim 1 in which a soot removing device is arranged in the gas tight passage of the heat exchange means, said soot removing device comprising a vertical pivot mounted centrally of the uppermost of said first pair of spaced plates, arms extending alternately radially and axially from said vertical pivot within said successive alternating radial and cylindrical passages and cleaning elements mounted on said arms to knock the soot ofl of the walls of said passages.

4. A heating device for heating fluid comprising wall means forming a combustion chamber, 'a flue connection, a heat exchange flue portion to receive combustion gases from said combustion chamber and to conduct them to said flue connection, a casing surrounding and spaced from said combustion chamber and said heat exchange fluid portion having at least one inlet passage for fluid to be heated and at least one outlet for heated fluid, said flue connection extending from said heat exchange flue portion through said casing, said wall means comprising a generally cylindrical wall, a closed bottom, and a top closed except for an axial cylindrical gas outlet flue mounted on said top, said heat exchange flue portion constituting a continuous gas tight tortuous passage leading from said cylindrical gas outlet flue to said flue connection through said casing and providing an interior hollow fluid heating space, said heat exchange flue portion comprising a first pair of spaced plates lying in parallel planes normal to the axis of said combustion chamber forming a first horizontal passage portion, one of said plates forming a radial extension of the top edge of said cylindrical gas outlet flue, and comprising successive pairs of coaxial spaced cylinders forming Walls of successive cylindrical passages and axially spaced radially extending plate elements connecting each pair of spaced cylinders with a succeeding pair of spaced cylinders to form at least one horizontal passage therebe' tween, said heat exchange flue portion terminating with a last pair of radially extending plate elements connected by a cylindrical wall spaced radially inwardly of the next preceding pair of spaced cylinders, the uppermost of said last-mentioned pairs of radially extending plate elements being provided with an opening from which said flue connection extends through said casing, a shell about said combustion chamber spaced from said combustion chamber and from said casing and extending upwardly about but spaced from said cylindrical flue gas outlet, said shell being open at its top and closed at its bottom and being provided with a heated fluid outlet adjacent its lower end extending through said casing, means forming a second outlet for heated fluid extending through said casing above said heat exchange flue portion, an open bottomed shell forming an inward extension of said second outlet for heated fluid, said shell extending inwardly from said casing in spaced relation to the walls of said heat exchange flue portion through the space surrounded by the cylindrical wall connecting the spaced radially extending plate elements at the termination of said heat exchange portion and between the walls of successive cylindrical passages and spaced therefrom, and said shell forming a baflie whereby air flowing from the space heween the heat exchange flue portion and said casing is led inwardly into the hollow space within said heat exchange flue portion into heat exchange contact with the walls of said hollow space and thence to said second outlet.

5. The heating device of claim 4 in which said open bottomed shell forming an inward extension of said 'second outlet is supported in said heat exchange flue portion by means of webs bearing on a wall of said heat exchange flue portion.

6. A heating device as claimed in claim 4 in which said open bottomed shell is supported by said heat exchange flue portion at its termination.

7. The heating device of claim 4 in which said inlet passage for fluid to be heated is provided adjacent the lower end of said combustion chamber and a second inlet passage is provided adjacent the lowermost portion of said heat exchange flue portion, and a partition is provided between the lowermost portion of said heat exchange flue portion and said casing below said second inlet passage whereby a first fluid can flow in heat exchange relation with said combustion chamber and a second fluid can flow in heat exchange relation with said heat exchange flue portion.

References Cited in the file of this patent UNITED STATES PATENTS 39,3 Dowling Aug. 4, 1863 281,795 Ridgway July 24, 1883 397,154 Turner Feb. 5, 1889 400,886 Williams Apr. 2, 1889 807,097 Stran Dec. 12, 1905 919,966 Short Apr. 27, 1909 966,064 Wallace Aug. 2, 1910 1,074,194 Pascoe Sept. 30, 1913 1,601,171 Grether Sept. 28, 1926 2,160,509 Lindsay May 30, 1939 2,205,451 Woolery June 25, 1940 2,345,559 Fraser Apr. 4, 1944 2,420,875 Frentzel et al May 20, 1947 2,704,062 Beyerman Mar. 15, 1955 FOREIGN PATENTS 492,838 Canada May 12, 1953 

